89 
py 1 



THE CORNELL BOOK ON 

Artificial 

Incubation and 

Brooding' 

including Directions for Operating 

CORNELL 

Incubators (Si Brooders 

and PEEP-O'-DAY BROODERS 



By E. C. HUFFAKER, C. E. 



CORNELL INCUBATOR MFG. CO. 



PRICE, FIFTY CENTS 



Copyrighted, 1903, by the Cornell Incubator Mfg. Co. All rights reserved 
PublisHed by 

Cornell Incubator Mfg. Co. 

ITHACA, N. Y.. U, S. A. 



Union & Advertiser Press, Rochester. 



THE CORNELL BOOK 

ON 

Artificial Incubation and 
Brooding 

INCLUDING DIRECTIONS FOR OPERATING 

CORNELL INCUBATORS and BROODERS 
AND Peep-O'-Day Brooders 



By E. C. HUFFAKER, C. E. 



Cornell Incubator Manufacturing Co. 



PRICE, FIFTY CENTS 

Copyrighted, igoj , by the Cornell Incubator Mfg. Co. All righ'ls resirved 

\ 

PUBLISHED BY 

Cornell Incubator Manufacturing Co. 

Ithaca, New York, U. S. A. 






LIBRARY OFj 
)NGRESS, 1 



THE 
CON 

Ons- O.r.f- SnCFrucD 

Ft. .a 

CLASS(\.XXo, No 



Publisher's Notice 



This book, like Cornell incubators and brooders, is a step ahead, 
neither copied nor quoted. It is as plain, practically speaking, as is 
consistent in treatin;^ the sul)ject "Artificial Incubation " scientifically; 
following nature's laws in a manner that will be instructive to those 
who may be interested in poultry raising, either by natural or artificial 
methods. 

The author has been ably assisted in the preparation b}^ a series of 
patient, painstaking, and costh' laboratory experiments, which have 
been carried on during the seasons of 1900, 1901, 1902, by skilled physi- 
cists connected with the Cornell crew. 

There is not an incubator on the market, and we feel safe in saying 

there likely never will be, whose projectors will have been to so much 

expense in perfecting as have been those of the Cornell. If the Cornell 

machines, together with this book, prove the means of helping those 

who have previoush' found artificial incubation unsatisfactory; and 

successfully aid the majority over the hard places in poultry raising, we 

will be amplv repaid. 

CORNELL INCUBATOR MFG. CO. 



Contents 



I. Directions for Opkratixc, thic Cornell Incibators 5 

II. Directions i'or Oreratinc, tiiI'; Cornicll Broodier . 14 

III. The IxcriiAToR . . . . . 16 

I\'. Tin-; Hex ...... 20 

V. The 1';g(; ...... 22 

VI. The CtEr.m ...... 24 

VII. The BlastodivRm ..... 25 

VIII. The Amxiox ...... 26 

IX. The rMini.ic.vL X'esicdc .... 33 

X. The Am.axtois ...... 36 

XI. The Kmurvo ..... 42 

XII. Peer o'Dav Brooders — Directions for Operating 45 



Directions for Operating the 
Cornell Incubators 



I 

BY H. H. BLACKMAN 



1. Carefully unpack your incubator and see that it is properly set 
up, screwing the legs tight to the cabinet case. It is necessar}- that 
the toi3 of the incubator be perfectly level. Test with a spirit level both 
" North and South " and " East and West." 

2. Fill the lamp and light it, adjusting ,so that it gives a large, 
clear and even fianie, without smoking. ITsually better satisfaction is 
obtained, and it is also considered economical, to use the best grade of 
kerosene oil. 

3. See that the regulator works freely. Place the thermometer 
on a slat of the egg tray, sliding the flange of the thermometer i;nder 
the metal clasp, which holds it firm and in the proper position at 
all times. 

* 4. Heat the machine to 100° adjusting the regulator by turning 
thumb-nut ; turning down opens the valve and lowers the temperature; 
turning up closes the valve and raises the temperature. 

5. Never have the temperature of an einptv machine more than 
101°. Carefull}' adjust the regulator before the eggs are put in so that 
the damper or disc-valve over the lamp chimney is open about one- 
fourth of an inch, when the thermometer on the tray is at 101°. 

6. Run the machine two or three days before putting eggs in, so 
that 3'ou will thoroughly understand its operation and get it nicely 
adjusted. 

7. If 3-ou thus far have everything as directed, you are ready to 
place eggs in the tray, with the bulb of the thermometer between and 
against two eggs. Allow some hours for the eggs to become lieated and 
do not change the regulator until the disc-valve is well opened. See 



* The adjusting device will be found beneath the table top. Remove the pocket 
cover to reach " thumb-nut." 



that the temperature never gets above 102°, except at hatching time, 
when it will and may rise to 104°. 

8. Use only eggs which you know to be fresh, well fertilized and 
from healthy stock. In order to get the best results the room in which 
3'ou have the incubator should be dry and well ventilated ; the temper- 
ature holding as near 60° as possible night and day. 

9. Eggs should be tested on the evening of the sixth day, when all 
eggs that do not show a strong, healthy germ should be taken out. The 
second test should be on the evening of the sixteenth day, when all that 
look unfavorable should be taken out. 

10. Begin turning the eggs on the fourth day, and turn at a regular 
stated time, morning and evening, until the eighteenth day. Discon- 
tinue turning on the eighteenth day. Each incubator is supplied with 
an extra traN- for turning. Turning is done b\' first taking the tray of 
eggs out of machine and putting on top of the incubator, placing the 
extra tray over the one containing the eggs, and turning or inverting 
both together. The machine should be kept closed while turning or 
testing the eggs. 

1 1. Cooling eggs should begin on the fourth day at noon, and they 
should be cooled each da}' at noon until the eighteenth day. Discon- 
tinue cooling on the eighteenth day. To cool the eggs, take the tray of 
eggs out of machine, placing it on top. Keep the door closed while 
eggs are out of machine. Be sure that the thermometer bulb is resting 
against two live, fertile eggs; cool down to 85°, or 90°. Care should 
be taken not to cool below 85°. The room should be so ventilated that 
there will be no draft on the machine. This would be very injurious, 
chilling the germs instead of cooling them. 

12. Eggs vShould not be turned or cooled, neither should the 
incubator door be opened after they begin to ])ip or hatch. 

Moisture and Ventilation 

The ventilating slide of the incubator should be gradually opened 
until wide open when the chicks begin pipping. Instructions regarding 
the proper supply of moisture and ventilation, at all times, can only be 
given correctly with the Cornell machines, for the reason that other 
incubators have different systems of heating and ventilating. 

Webster tells us that diffusion is an extensioti, dispersion, or circula- 
tion that spreads widely, or 3.n even 2inA proper spreading . Our system 
amounts simply to a perfect method of ventilation, and unless your 
incubator has this system it will never give the best results. 

Our advice is : Start vour machine with the outlet or ventilating 



slide partly open, say one-fourth. Then by using the egg tester every 
two or three evenings, and comparing the size of the air cell with the 
lines and dates on the drawings which show approximately the proper 
size of air cell in hen or duck eggs at various dates, during period of 
incubation, you can tell whether you need more or less ventilation. 

Never put water in the moisture pans until \'ou find the eggs need 
it. If you find the air cell is too small, in other words that the egg is 
not drying away fast enough as compared with the following drawings 
you should open the ventilator wider. On the other hand if you find 



duck's egg 




HENS EGG 

1 




the eggs are dr^-ing awaj- too fast, you should close the ventilator a 
little. 

The sliding ventilator should never be completely closed, and for 
this reason, should you find the eggs drj-ing away too fast or the air 
cell getting too large, you can retard the evaporation b}' putting water 
in the pans. Experiments have proven that lukewarm water should be 
j)ut in the pans on the evening of the eighteenth da}' a>/yTi'ay, and the 
ventilating slide opened wide. 

Experiments have also proven that different localities require a 
different management of ventilation, equivalent to the proper or natural 
supply of moisture ; as do also clie different seasons of the year. For 



7 



these reasons we have been able to prove, throug-h the results of many- 
careful experiments which have been conducted by experts connected 
with the company, that an incubator with a fixed ventilation cannot 
give general satisfaction, and so have we also proven an incubator 
should not be built and sold without being fitted and supplied wnth 
moisture pans. While a person operating a Cornell incubator, favorably 
located, at certain seasons of the j'ear, in New York State, may never 
have occasion to use supplied moisture, yet manufacturers cannot hon- 
estly claim this of localities like Colorado, and the same comparison 
will apply to tlie different vSeasons of the j^ear as well as to the different 
localities. 

Placing the Machine 

A room in which to run an incubator for satisfactory results, should 
be protected, to avoid the extreme changes of temperature. The tem- 
perature of the room should be kept at all times as nearU' as possible to 
60°. It is essential that the room should be properly ventilated, so that 
the air is kept pure and sweet ; in fact, so that one cannot detect the 
odor from tlie lamp when entering the room from the fresh air out doors. 
Remember tliat in the egg there is life, which is very easil}' destroyed 
by poisonous gases and impure air. 

The incubator should be so placed in the room that the sun cannot 
shine u]K)n it. Cireat care should also be used in ventilating the room 
so as not to cause a drauglit. Tlie incubator should be so placed that it 
is practically impossible to cause a draught across it from open doors or 
windows. 

Attention to the Lamp 

The proper time to fill the lamp is after turning the eggs each 
evening, which regular attention is necessar}-. It is advisable from an 
economical point of view to use the best grade of kerosene oil obtain- 
able. The wick should be trimmed every day, using a knife blade to 
remove the charred particles, instead of cutting the wick. A clear, true 
flame suflicient to keep the disc-valve slightly open should be main- 
tained. Keep all parts of the lamp scrupulously clean, as a dirty lamp 
is not only more liable to smoke, but smells badly, tainting the air. One 
should always watch the lamp a few moments after lighting, as the 
flame is liable to run up when the burner gets hot. If not cared for 
properly in this respect, the lamp will smoke, which is to be avoided, 



as an accumulation of lampblack in any lamp or heater is likely to 
itrnite and cause trouble. 



Placing the Eggs 

The eggs should be placed on the tray in rows, with the small ends 
slightly depressed (the lowest), and all the eggs intended to be incubated 
in any particular hatch should be started at one time. Do not add eggs 
to those already in, after the machine is once started. The selection of 
eggs to be placed in the machine being the most important part, great 
care and judgment should be iised. First, the eggs must be fresh ; the 
fresher the better. The fertility and vitality of the eggs will depend 
chiefly on the vigor of the parent stock. The principal conditions 
necessary to the fertilization of eggs are simply those which will insure 
good health to the parent stock. 

Temperature 

Heat the q%^ chamber to ioi° and no higher, before placing the 
eggs on the trays. When it is running at ioi°, place the eggs in the 
machine and allow several hours to elapse without changing the regu- 
lator, as it will take time for the eggs to become heated. Watch the 
thermometer and see that it does not get above 102°. Between 101° and 
102° is the proper temperature for hen and duck eggs for the first week 
of incubation. During the second and third weeks the temperature may 
run from 102° to 103°. It is essential that the thermometer bulb should 
rest between and against two live, fertile eggs. A low temperature is 
less dangerous than a high one, as it may not kill, but will if continued, 
lengthen the time of incubation and weak chickens will result. 

Be sure that the thermometer, after the fifth day, is resting against 
two fertile eggs ; this may be ascertained by using the ^'g^ tester. As 
we have stated, the temperature of the fertile eggs is from two to three 
degrees higher than that of infertile, or dead ones. If the thermometer 
bulb is against infertile eggs and at 103°, the fertile eggs ma\', unknown 
to the operator, be at 105° or 106°. Apparent fluctuations of the tem- 
perature are frequently due to changing the thermometer from fertile to 
infertile eggs. 

The thermometer should be placed three or four rows back, facing 
the front so it can be easily read through the glass door without open- 
ing the machine. Do not change the regulator, or bother about the 



temperature after the chicks begin to hatch. Tlie temperature, as 
stated, may at hatching time rise to 104° or 105° without danger, as it 
is caused by the animal heat from the hatching chicks. 

The Regulator 

The reguLitor is perfectly simple and easily understood. The 
thermostat is inside the agy^ chamber directh- over the eggs. With the 
slightest change of temperature it automatically raises or lowers the rod 
connecting it with the carefully balanced regulator bar encased beneath 
the clear, smooth top of the machine, tilting the bar so as to open or 
close the disc valve over the chimney. This governs the amount of 
heat supplied to the machine. 

If one is particular in the adjustment, the regulator will work 
easily and freel}- ; responding quickly to a fraction of a degree's varia- 
tion of the temperature in the egg chamber. Tlie adjustment is made b}' 
turning the thumb-nut on the rod whicli connects the thermostat and 
regulator bar. This should be adjusted until the disc valve is opened 
about one-quarter of an inch, when the thermometer is at 101° or 102°. 
Turning the tliuml)-nut do7C')i opens tlie valve and lowers the tempera- 
ture ; turning it ''/> closes the valve and raises the temperature. 

Turning Eggs 

Man}- devices have appeared f(jr turning eggs, but the best and 
only practical way is by the use of an extra tray which we furnisli with 
each machine. Remove the tra}' containing eggs, from the machine, 
place the extra tray over it in an inverted position so that the eggs are 
encased between the two trays, then grasp both trays with the hands on 
opposite sides, raising the trays, turning them to or from 30U, .so that 
the eggs are transferred from one tray to the other with tlie large ends 
.slighth- elevated. Remove the top tray, see that each egg is in its 
proper position, with small end dei)res.sed, then replace the tra\- in the 
machine. This should be done twice each day after the third day. We 
advise that you establish a system in this respect, and turn the eggs at 
a regular stated time morning and evening, beginning on the fourth 
dav and discontinue on the eiirhteenth dav. 



10 



Cooling Eggs 

Begin to cool the eggs on the fourth day at noon, and cool them 
each day at noon, until the nineteenth da}'. To cool the eggs, place the 
tray with eggs on top of machine, being sure that the thermometer bulb 
is resting between and against two live, fertile eggs. When cooled to 
85° or 90° replace in machine, care being taken to never cool below 85°. 
During cooling, the door of the incubator should never be left open ; 
excepting perhaps during ver}- warm weather, when it has been found 
more satisfactory- to cool the eggs in the machine, by opening the door ; 
not leaving it open ver}- long at first, gradually increasing the time as 
the hatch progresses, from five to twent3'-five minutes, and as above 
stated, never allow the temperature to go below 85° when cooling. 

Testing the Eggs 

This is a very imjjortant matter and one that should not be 
neglected. Success largely depends upon careful testing and the 




operator's care and attention in following these instructions. Right 
here we wish to sa}- : persons operating Cornell machines are expected 
to follozv these instructions and not some one's suggested ideas, or un- 
substantiated theories. If our instructions are carefully followed the 
results will be most gratifying. 

We furnish an egg tester with each machine, which can be used 



I I 



on a small hand lamp in place of a chimney. The room should be 
darkened, and for this reason we recommend testing in the evening. 
The tray of eggs should be taken out and placed on top of machine and 
the door closed. Have the lamp with tester at hand, and hold each egg 
in front and tight to the opening of felt on tester, when you can readily 
see the developing germ on the iifth or sixth day. All eggs not show- 
ing a developing germ on the evening of the sixth day should be thrown 
out. The embryo should not show in sharp outline, or too near the 
shell and the blood vessels should not appear excessively bright red. 
On the seventh day the eye becomes visible as a large, dark, blurred spot. 
From the eighth to the twelfth day the movements of the embr3'o ma}- be 
distinctly seen. Infertile eggs remain quite clear, resembling fresh 
eggs except for the increase in the size of the air cell. Where the germ 
or embryo starts and then dies within the first week of incul)ation, the 
blood may collect in a bright red circular vein, forming the so-called 
" blood ring. " The fertile egg with a strong health}' germ becomes 
darker each day until on the eighteenth day it is very opaque, excepting 
the air cell. 

Preparing for the Hatch 

Before the eggs begin to hatch, say on the evening of the eighteenth 
day, remove the galvanized strip found in each tra\-, leaving an open- 
ing through which the chicks will pass as they crowd forward to the 
light. This end of the tray should be toward the front of the machine. 
The bottom of the nursery underneath the egg tray should be covered 
with the nursery tray, or burlap frame, provided for the purpose. This 
tray also enables 30U to keep the machine perfectly' clean and pure. 
After pipping of the shells begins, the door of the incubator should not 
be opened, except for refilling of the water pans, in case the air is not 
sufficienth' moist, so the chicks come out moist, and without the 
membrane being dried fast. The door should not be opened until every 
chick is hatched, and is perfectly dry. 

Hatching Time 

During the winter and early spring months 3-ou shoixld not expect 
such large hatches as during the natural hatching season. The best 
results and largest percentages are hatched in the late spring, that being 
the natural season. Fowls lay the largest number of eggs at this 
season, and a larger percentage of the eggs are fertile, will hatch better, 
and the chicks will be more vigorous. Taking the whole season into 

12 



consideration, seventy-five per cent of fertile eggs is a large average. 
A larger percentage than this is unusually good, but some of the germs 
are liable to be weak. Hen eggs usually begin hatching on the nine- 
teenth day. Careless opening of the door might prove fatal by chilling 
the wet chicks just hatched or causing those which have pipped, to stick 
fast to the shell and making it impossible for them to get out. How- 
ever, if you follow these instructions carefulh*, yoii will have no trouble 
in hatching everj' Qgg which nature intended should be hatched. 

Notes of Importance. 

Never close the ventilating slide completely. Never let your lamp 
get empty, and always have enough flame turned on to keep a constant 
strain on the regulator — if the disc valve or damper does remain open 
five or twenty minutes at a time do not turn the lamp down. 

When life begins to be generated in the eggs, it will produce animal 
heat which will increase with the age of the embryo. The heat will, in 
consequence gradually run up ; then you will have to adjust the regu- 
lator accordingly. Adjust as often as necessary to hold the temperature 
to 102°, rather a trifle below than above. 

Use the egg tester, and dry the eggs down to one-fourth or one-fifth 
of the contents of the shell by the time hatching begins. 

Turning and cooling should be discontinued on the eighteenth daj^ 
for hen eggs and on the twenty-sixth day for duck eggs. 

Great care should be taken not to let the temperature run down 
when hatching, as it will cause the chicks to stick to the shell and die 
there. 

Cornell Incubators and Brooders are hot air machines. Thev will 
hatch every egg that nature intended should hatch, and the chicks will 
be healthier, stronger, and more vigorous than can be hatched with any 
other incubator on the market. Careful experimenting has proven this 
beyond a doubt. 

If through negligence you should happen to get a poor hatch, do 
not blame the machine. Thousands of successful operators are speak- 
ing in the most favorable terms, with regard to the satisfactory work of 
the Cornell, as is proven by the testimonials in our catalogue, all from 
prominent and well-known poultrymen. 

An3-one is liable to have a poor hatch. The result may be from one 
of many causes. For instance, the operator can't understand the 
instructions ; has not taken time to read them ; and being very busy 
probably would not have followed them if he had taken time to carefully 

13 



read them. This is a very common cause, and then when a poor hatch 
is the result, the machine and the manufacturer are blamed for it all, 
when there could not be a greater injustice. 

Do not be over-anxious ; use care and judgment in selecting vour 
eggs. Beware of old eggs, chilled eggs, (eggs do not have to freeze to 
chill), and eggs from ill-fed or ill-bred breeding stock. 

II 

The Brooder 

The chicks should remain in the incubator twentj'-four hours after 
hatching. During this time they should be given no food. In the 
meantime the brooder should be gotten ready and warmed up until there 
is a regular temperature of 90° at about two inches above the floor, 
under the hover. The chicks should be convcn'ed careful!}- and without 
chilling from the incubator to the brooder. With a little care and train- 
ing during the first day or two, the chicks will quickly adapt themselves 
to the comfortable and attractive conditions of the hover of the brooder, 
which is heated automaticalh', and is practically as near Nature or 
mother hen as may be. 

By putting the chicks into the brooder the temperature will, if 
there be a very large number of chicks, rise to 95°, possibly higher, at 
first. The temperature should be gradually regulated down until it 
averages about 75° in the third and fourth week after hatching. Always 
take the temperature from about two inches above the floor under the 
hover. 

Care and Feeding 

Outdoor brooders are ordinarih- not intended to be used out of 
doors in the winter. An outdoor brooder is usuall}- intended to be used 
out of doors when the season and weather permit of the chicks exercis- 
ing or running on the ground outside. The Northern States during 
January, February and March — the three most profitable months for 
hatching — are so liable to extremes of temperature, strong winds and 
severe storms, that the brooder should, if possible, be placed in a brooder 
house, poultry house, or a well-lighted, comfortably protected shed or 
shelter of some kind. Chick grit, coarse sand or fine gravel should be 
thrown over the floor of the brooder and exercising compartment ; then 
a thin layer of chaff or finely cut clover, and a small quantity (not more 
than they would eat up in five minutes if placed where they could get it 

14 



readily) of baby chick food, rolled oats or any other dry granulated 
grain scattered frequently — say four times a day in this litter on the 
brooder floor. Their food should include besides the grains and meal, 
scraps and bones, some green food. Lettuce is excellent, also cabbage 
leaves, if fresh and crisp. Green cut clover is also good ; finely cut, 
drj' clover, steam -cooked, will answer when you cannot get anything 
better. 

Avoid sloppy foods and guard against overheating or chilling the 
chicks, which conditions might produce diarrhoea. The brooder should 
be kept clean, and a water fountain constantly supplied with fresh 
water, from the first moment the chicks are placed in the brooder, 
should be kept before them. 

Concluding, we wish to state that our interest in your success does 
notecase as soon as we receive your order for incubators or brooders, 
and obtain the pay for the machines. If you have the slightest diffi- 
culty in operating, we will be glad to help you to the full extent of otir 
ability-, and letters from customers asking advice will always be cheer- 
fully responded to. 

Since the above directions were written the Cornell Incubator Mfg. 
Co. has acquired the business, patents and good will of the Peep-O'-Day 
Brooder indu,str3', and the directions shown herewith relating to the 
Cornell Brooders will apply to the Peep-O'-Day as well. 

The Cornell Incubator Mfg. Co. will exercise the same care and 
diligence in the construction of the Peep-O'-Day Brooders and special- 
ties as has always been shown in all of the products of the Cornell 
factory. 

In General 

Read the following pages carefully. A few technical terms are 
used, but do not let these frighten you. Once thoroughly understood 
you will derive inestimable benefit from a careful reading and study of 
the text. 



15 



Artificial Incubation 

BV C. E. HUFFAKER 
III 

The Incubator 

1. Artificial incubation as an industn'is scarcely more than twenty 
years old, yet in that vshort space of time its growth has been enormous 
and is destined to be still more gigantic. The growing scarcity of game 
birds of all kinds, coincident with the increase in population and the 
accumulation of wealth, has created a demand for domestic birds, which 
is constantly growing. 

Furthermore, the general introduction of incubators has rendered it 
possible to supply the tables of the well-to-do with young birds out of 
season, and of a quality superior to that formerly obtained in the 
natural way. Having made up his mind that quail and snipe and wild 
duck and ortolan are no longer to be had, the epicure's thoughts are 
now turned to broilers and roasters and Pekin ducks. He insists only 
that the}' shall be of the best quality obtainable. For such, he is will- 
ing to pay ])rices which will in the future doubtless appear fabulous. 

2. From the first of January- until the first of September, broilers 
may be vSold in the open markets for from fifteen to forty-five cents per 
pound, roasters may be sold for sixteen cents, and ducks are accounted 
low at fourteen cents per pound. The cost of food in producing these 
birds has been found not to exceed five cents per pound, eggs for incu- 
bation may be had at from one to four cents each, oil for incubating and 
brooding will cost about half as much as the eggs. These are the chief 
items of expense, and it is evidentthat with reasonable success in hatch- 
ing and rearing, the gains will be large, compared with profits obtained 
through raising cattle and hogs. 

3. That the high prices of broilers will continue for many j'ears to 
come is manifest from the fact that the great bulk of them must be pro- 
duced by artificial methods, and that dependence must be placed upon 
individual operators rather than upon a few great broiler plants, so that 
the suppl}- is not likely to equal the demand until the number of incu- 
bators is greatly multiplied. 

16 



4. The cost of an incubator of two hundred egg capacity, with 
brooders to accommodate the chicks, is less than that of two good cows, 
and the expense of running them will about equal the cost of feed for 
the cows. It takes less room to accommodate them and less time to 
look after them, while the profits which may result from intelligent 
management of the machines will exceed any that can possibly be made 
from the cows. 

5. While it would not be wise to place an incubator in the hands of 
a ten-year-old boy, who usually has the faculty of leaving his tasks un- 
finished, the work is admirably suited to boys and girls a few years 
older, who are oftener than otherwise destitute of employment and only 
too glad to have an opportunity for making money for themselves. 
Even where they have other employment they may still successfully run 
an incubator, as the principal part of the work may be done at night. 
The incubator also offers profital:)le employment to those mothers, who 
are in straitened circumstances but whose domestic duties prevent their 
seeking employment away from home. Ivspecially is it adapted to the 
use of the farmer's wife whose surroundings and experience with natural 
methods eminently fit her for the work. 

6. The three problems which the inventors of incubators have 
sought to solve are the economical application of heat to the eggs and 
its regulation ; the uniform ventilation of the egg chamber ; and the 
regulation of the supply of moisture. 

Of these the first has been more satisfactorily solved than either of 
the others. This is due to the fact that while the temperature of the 
egg chamber can be accurately determined by means of a thermometer, 
we have no common instruments for determining the amount of air and 
moisture passing through. We have also in the variations of the 
temperature a force of sufiicient intensity to set in motion mechanical 
devices by means of which the degree of heat in the egg chamber may 
be automatically controlled. By this we mean to say that while the 
outside temperature may vary many degrees, or the flame of the lamp 
which supplies the heat may be turned high or low, the temperature in 
the chamber will either not vary at all, (in which case the regulation of 
the heat would be perfect), or the variations will be less pronounced 
than they would be if the regulator were not used. 

On the contrary tlie slow passage of the air through the chamber, 
by which ventilation is effected, is so slight as to be wholly unavail- 
able for operating mechanical devices, however delicate, so that we have 
no direct means of regulating the ventilation through its own varia- 
tions. In the same wa}' automatic regulation of the supply of moisture 
through variations in its amount, is impossible. 

17 



7- The .source of life in an incubator is tlie heat, which by its rari- 
fying force starts two currents of air, by one of which the hot fumes 
from the lamp are carried through the heater, while the other drives a 
slow current of pure air over the eggs. Upon the latter current ventil- 
ation depends. In one type of incubator the heater takes the form of a 
drum overlying the egg chamber and the ventilating current rises 
through the chamber, being introduced as cold air through apertures 
in the bottom and escaping as warm air near the level of the drum. 
In this type of incubator it is evident that the amount of ventilation 
will var}^ almost directly as the outside temperature, and can only be 
regitlated by hand. 

In another type the heated air surrounding the lamp chimne}' is 
carried to the top of the machine, thence is deflected downward through 
the egg cham])er, and passes out at the bottom into one or more tubes 
by which it is again carried to the top of the machine and allowed to 
escape. As in the preceding tj'pe, the ventilation will var}- as the 
outside temperature and is in no sense automatic in its regulation. 

In still another type the heater lies wholly outside the machine and 
the ventilating current after being deflected downward through the egg 
chamber is withdrawn at the bottom of the chamber and returned to 
the heater, the ventilation being feebly automatic but in the main 
varN-ing with the outside temperature. 

These are the princi])al types of incubators made, and in none of 
them is the ventilation clearly automatic. The manufacturers of 
the Cornell Incubator have, however, recenth" introduced a new feature 
which seems to justify- them in claiming that their machines are auto- 
matically ventilated. The ventilating current passes first upward 
through an external heater into the top of the egg chamber, is deflected 
downward and allowed to pass or diffuse through the false bottom 
of the incubator, thence into the left end wall and forced to pass 
out through the graduated ventilating slide on that end of the 
machine. The Cornell does not use the same air over and over again, 
nor is the air surrounding the eggs left to stagnate. The carbonic acid 
gas, escaping from the growing embryos through the porous shells of 
the eggs, is carried off and away by the current of air, and not 
returned through the heater to poison the atmosphere surrounding the 
eggs. Variations in the outside temperature will in this case have 
but little effect on the ventilation, since the driving force is the differ- 
ence in weight of equal columns of air in the heater and in the egg 
chamber. The temperature in the egg chamber is practically constant 
and the ventilation will therefore vary as does the temperature in the 
heater outside thechimne}', which carries the fumes from the lamp. If 

18 



the outside temperature sliould fall, the damper above the heater will 
descend, through the operation of the thermostat, and the temperature 
of the heater will rise. The fumes are now deflected in greater volume 
through the pipes which traverse the space above the egg chamber. It 
will be seen therefore that the temperature of the chamber is maintained 
chiefly b}^ the increased flow of hot air through these pipes and not 
through the increased temperature of the fresh air in the heater, which 
remains nearl}- constant. The ventilation is therefore automatically 
regulated in the strict sense of the term. 

8. Very little progress has as j'et been made in the way of auto- 
luaticalU' regulating the supply of moisture, though the manufacturers 
of the " no -moisture " class of machines claim that by properly adjust- 
ing the amount and distribution of ventilation, the addition of moisture 
is no longer necessar}-. In these machines advantage is taken of the 
principle that the vapor of water contained in the air constantly tends 
to rise on account of its relatively low specific gravity, and that it may 
be arrested and accumulated in any inclosed space, like the egg chamber 
of an incubator, through which it may be passing ; provided the move- 
ment of the air be sufficiently slow and its course downward. The 
moisture in the ventilating ci:rrent is thus in part left behind in its 
descent through the chamber. It is evident that any incubator ma}' be 
converted into a "no-moisture" machine by simply diminishing the 
ventilation. The regulation of the suppl}^ in this manner cannot, how- 
ever, be considered automatic. 

9. Even conditions throughout the egg chamber is the great 
desideratum in any incubator, and such is the rivalry between the lead- 
ing manufacturers that not a stone is being left unturned in the 
development and perfection of their several machines. In selecting an 
incubator one should bear in inind that it costs any manufacturer quite 
a sum to build a good machine, and that man}- of the "cheap" machines 
are really worthless. The beginner may purchase any good machine 
with a reasonable assurance of success. It is best to purchase outright 
rather than on trial. The best guaranty one can have is the unqualified 
agreement of the manufacturers to take back the machine and refund 
the purchase money if the purchaser is dissatisfied. 



19 



IV 
The Hen 

10. There are man}' persons who believe that Nature, like the king, 
can do no wrong-, and that we can never hope to equal her accomplish- 
ments by artificial methods. A Russian once thought differently, and 
decided to test the matter by means of fish eggs. Nothing could be 
more unnati:ral than the impregnation of such eggs on dry land and in 
a tin pan having no water in it. Yet this is what the Russian attempt- 
ed and with such signal success that his method has superseded 
Nature's in all the great fish hatcheries throughout the world. 

It is not in man's power to produce an egg artificially, but given 
the egg he may hatch it, even with more uniform success than the hen. 
This follows from the fact that he may obtain better control over the 
conditions of incubation than the hen is al)le to do. At one time the 
hen brings off a full brood of chicks, at another a small one. At one 
time eggs are reported to be hatching well all over the country, at an- 
other the hatches are everywhere poor. The only rational explanation 
of this is that in some cases the hatches are made under more favorable 
conditions than in others. 

11. The hen supplies the eggs with heat, ventilation and a certain 
amount of moisture through the insensible perspiration from her body, 
but while the heat of her bod}- is ver\' nearly constant, the temperature 
of the egg will also depend upon the temperature of the air, the char- 
acter of her nest, and the number of eggs ; the ventilation will vary 
with the character and location of the nest and with the sea.son ; while 
the amount of moisture which the eggs receive will depend upon the 
humidit}' of the air, tlie character of the nest and its proximity to the 
ground. Her control of the conditions is therefore but partial, and the 
sum total of all conditions may be either favorable or otherwise. The 
hen accordingly offers us no certain indication as to what the most 
favorable conditions are, and a study of natural incubation leaves us 
in doubt as to the best course to pursue in artificial incubation. 
Nevertheless such study is exceedingly valuable, though it may not in 
all cases be entirely conclusive. 

12. We may learn from the hen that tlie temperature of the eggs 
during incubation should be about 103°, though somewhat less during 
the first one or two daj^s, while the nest is becoming warmed up, and 
greater during the last week when the animal heat developed by the 
chicks runs the temperature up. 

20 



At irregular intervals the hen leaves her nest, even when supplied 
with food and water, allows the eggs to cool. Just what purpose is 
served in cooling the eggs is not clear, but it has become the almost 
universal practice in artificial incubation to follow nature and cool the 

The hen not onl}- cools her eggs but turns them as well. She does 
so by pressing the outer edges downward into the interior of the 
nest, those within being forced outward. It is possible that she does so 
to equalize the temperature, and that the turning is incidental. However, 
the general practice is to turn them when incubated artificiall}-. This 
is done either by hand or by means of an extra tray. In most incu- 
bators it has likewi.se been found beneficial to shift them occasionally 
into new positions. 

In the wild state the hen probably constructed her nest as the 
pheasant and the wild turke\' do to-daj', in the woods, close upon the 
ground, and with only a thin layer of dead leaves intervening between 
the eggs and the damp earth. Hence in a state of nature the eggs 
probabl}' received a liberal su])])ly of moisture from the nest and the 
underlying earth. This wild instinct is still observable in those hens 
which secrete their nests in the woods or among clumps of bushes, and 
it is noticeable that such hens usuall}' come off with large broods. 

The general experience of farmers' wives is that turke3'S do much 
better when hatched and raised by their own mothers than when hens 
are used in raising them, and a possible explanation of the fact ma}' be 
that as the turkej' nests in the woods the eggs receive more moisture 
than when placed linder hens and under shelter. 

13. In order to obtain the best results, the laying stock should be 
in proper condition ; that is, the fowls should be free from disease, 
neither too fat nor too lean, and have access to such food as will produce 
an egg suitable for hatching, and to some form of calcium carbonate so 
that the shell nmy be properly developed. 

To what extent a diseased fowl may transmit her disease, or at least 
a predisposition to disease, to the chick, is a mooted question. Any 
chronic disease or constitutional infirmity may possibly be so trans- 
mitted, but it is doubtful if this is true of passing ailments. It seems 
more likely that when the hen is ill-fed or chilled, or otherwise out of 
condition, the constitution of the egg may not be altogether normal or 
suited to the proper development of the chick. 

Some experiments made by the writer with eggs from stock known 
to be weakened by disease gave very poor results. On the other hand, 
eggs from stock known to be in excellent condition hatched no better 
than others from stock in ordinarj^ condition. The results pbtained by 

21 



careful selection of eggs from good stocb.^have "b'e^n but little better 
than those obtained from village 'stores .' Apparently the eggs from 
scrubs and mongrels are as fertile and hatch as well as those from better 
stock. 



V 

The Egg 

14. The fowl's egg belongs to the class of meroblastic ova, in 
wliicli the germ is jjrovided with a supply of nourishment in the form 
of a volk, or vitcllus, inclosed in a yolk sac, or vitelline membrane. 
The 3-olk constitutes the true ovum, the white and the shell being in a 
sense extraneous. The white is 78 per cent water, and as the yolk, 
or true ovum, in the fresh egg is centrally located it is ,in effect sur- 
rounded l)y water and as trviU- immersed in it as the egg of a fish 
or a frog in a running brook. It is held in place by the weight and 
tension of two heavN' white cords, the chalazae, which ma\' be seen on 
breaking a fresh egg, and which connect the j-olk with the ends of 
the shell. 

I'nder the combined influence of air and heat the 3-olk floats slowly 
upward until it comes in contact with the shell and subsequenth' takes 
the form of its upper surface, in wdiich position it more readily absorbs 
oxygen from the air. 

The significance of this arrangement becomes apparent when we 
consider that the early embrj-onic development of any animal corre- 
sponds with the more coiuplete development of those occupying a lower 
place in the series of animal forms. Thus the early development of 
the chick is very similar to the more mature development of the 
fish and frog, and it seems altogether likeU* that in its early devel- 
oi)ment the ovum of the fowl's egg requires conditions of incubation 
similar to those which persist through the entire incu])ating period of 
the frog and fish, i. e., a complete submersion under water, which will 
be secured by keeping the j'olk in the middle of the egg. This is 
accomplished ])y keeping the egg cool prior to incubation and allowing 
the temperature to ri.se slowly after incubation begins, at the same 
time restricting the ventilation. 

When the hen goes on her nest, especially if it be located in a 
cool spot near the ground, one or two days will elapse before the tem- 
perature reaches its full height, and an incubator will be found to do 
best when the temperature is allowed to rise slowh'. Strange as it 

22 



may .seem, the development will be more rapid with a low than with 
a relatively high temperature, especially if accompanied with a small 
amount of ventilation. Just where the fish stage of development, if 
we may so term it, ends, we of course do not know ; but the operator 
will make no mistake in keeping the temperature down for three days, 
and at the same time greatly restricting the supply of air. 

15. The shell protects the contents of the egg from injur}-, at the 
same time that it limits the amount of ventilation. It is pierced by in- 
numerable pores which admit of the slow passage of air to the interior. 
The ejffect of moisture appears to be to partially close these pores 
through the swelling of the substance of the shell, and the consequent 
restriction of the ventilation. At any rate the addition of moisture 
answers the same purpose as shutting off the air. The shell is lined 
with a double membrane whose layers separate at the larger end of 
the egg to form an air space which enlarges through evaporation until 
at the end of the period of incubation it occupies more than one fourth 
of the volume of the shell. The growth of the air cell may, to a certain 
extent, be regulated b}' properly adjusting the supply of air and mois- 
ture, and is commonly regarded as an index to the amount of evapora- 
tion which has taken place. If at any stage of development it appears 
larger (when seen through the egg tester) than experience has shown 
it should be, moisture is to be added. This is a crude method of de- 
termining when moisture should be supplied to the eggs, and somewhat 
unsatisfactory as the evil following too much ventilation is detected 
too late. 

r6. In selecting eggs for hatching, it is well to examine them with 
an egg tester and to reject all those which are unusually large or 
small, as well as those which are irregular in form or whose shells 
have a mottled appearance. The latter seldom hatch except when abun- 
dantly supplied with moisture. It is preferable to use eggs of one 
color and if possible from a single breed of fowls. The IMediterranean 
class, including the Teghorns and Minorcas, lay white shelled eggs ; 
the classes of Asiatics, the Brahnuis and Cochins and Langshans, lay 
dark brown eggs ; while the American class, the Wyandottes and Ply- 
mouth Rocks, lay eggs which are either brown or white, according to 
the origin of the breed. The interior of the egg should in all cases be 
of a uniformly rich golden color when viewed through the egg tester. 



23 



VI 

The Germ 

17. Imbedded in the tipper surface of the 3'olk of a fertile egg- and 
inimediateh' beneath the vitelline membrane, lies a single spherical cell, 
known as the germ or germ-cell. Fertilization takes place in the 
oviduct and a certain stage of development is often reached before the 
egg is deposited. It consists for the luost part of a structureless mass of 
jirotoplasm, having an outer cell wall and a nucleus. So simple is it 
that scarcely anything more can be added in the way of describing its 
appearance, even when viewed through the most powerful microscope. 
Like other forms of protoplasm it is endowed with the mysterious 
principle of life, and possesses within its small compass forces of whose 
nature we are wholly ignorant. Almost all we know of it is that it can 
convert dead into living matter, that it can reproduce itself, that it 
forms the basis of all organized structures, and that it can be brought 
into existence onh' through the agency of pre-existing ])rotoplasm. In 
its simplest form and to a limited degree, it possesses the power of per- 
forming all the functions of all the bodily organs. 

It was once supposed that the germ-cell contained an extremely 
small chick, and that the process of development was one of enlarge- 
ment only ; but it is now known that such is not the case. On the 
contrary- the germ-cell does not possess organs of an^^ kind and its only 
evident function is to reproduce other cells, like itself, each of which in 
turn possesses the same power of reproduction. 

1 8. Cell reproduction takes place through division, each cell be- 
coming divided into two, and each half enlarging to the size of the 
original cell and being endowed with all its functions. The process is 
accompanied by a nnsterious coiling and uncoiling of a thread-like 
mass of a dark substance known as croinatin. Except in the arrange- 
ment of the cromatin threads and its manner of uncoiling there is 
scarcely any observable difference in the germ -cells of different animals. 
In chemical composition the cell is simple but in its molecular consti- 
tution it is thought to l)e inconceivably complex. The germ-cell loses 
much of its importance as soon as reproduction begins, as it then be- 
comes but one among man}' similar cells, all having similar functions. 



24 



VII 
The Blastoderm 

19. The cells produced from the original germ-cell b}- repeated sub- 
divisions do not develop equallv in all directions, but at first cohere to 
form a continous membrane known as the blastoderm, or germ-skin, 
whose growth is for the most part peripheral over the surface of the 
3'olk, immediatel}' beneath the vitelline membrane. The membrane has 
been rightly termed the germ-skin, as it resembles nothing else vSo much 
as the skin of an animal. The crowding together of the cells over the 
upper surface of the yolk gives to the membrane at first a morula, or 
mulberry appearance, while by a further lateral compression the cells 
become hexagonal in cross section, and the membrane uniform in 
texture. 

When viewed through the egg tester at the end of the first da}- of 
incubation, the blastoderm appears as a bright blush, indefinite in out- 
line, which by the end of the second day is as large as a silver quarter 
and deep scarlet in color. B3' the end of the third day the size has 
increased to that of a half dollar, the interior has grown lighter and 
the outer portion darker, so that the blastoderm now appears ring 
shaped. Subsequently the upper portion of the ring passes under the 
air cell, and the blastoderm assumes the appearance of a horseshoe or 
crescent. 

20. The blastoderm, which is at first a single membrane, splits in 
two, giving rise to an outer layer called the epiblast, or epiblastoderm, 
and an inner layer known as the hypoblast. There is subsequently 
developed between the two a middle la3'er called the mesoblast. Still 
later the mesoblast becomes divided into two la5-ers, the outer being 
termed the somato-pleure, or bodj- wall, and the inner the splanchno- 
pleure, or visceral wall. Thus in its final development the blastoderm 
comprises four distinct layers. From the outer of these, the epiblast, 
■will be formed the epidermis of the chick, the brain and spinal cord, 
the nerv^es, the eye, and parts of the ear and nose. From the inner, or 
hypoblast, the linings of the intestines and air passages. From the 
outer layer of the mesoblast the true skin, the voluntary muscles and 
the skeleton. From the inner layer of the mesoblast the heart, the ali- 
mentary canal and the larger blood vessels. 

21. From the different laj'ers of the blastoderm there are also de- 
veloped certain appendages, or temporary organs, the Amnion, the 
umbilical vesicle, and the allantois, which will be treated under sepa- 
rate chapters. These serve to nourish and protect the chick during 
its embryonic existence and disappear when it emerges from the shell. 

25 



VIII 
The Amnion 

22. While the blastoderm is in process of formation, by a periph- 
eral growth over the surface of the yolk, important changes are in 
progress at the original seat of the germ-cell, b}- which the dead mate- 
rials of the egg are being vitalized and fashioned into the rudiments of 
a chick, or embrN-o. 

2T,. The embryo first appears as a delicate furrow, called the primi- 
tive trace, in the epiblast, or upper la^-er of the blastoderm. The 
margins of this furrow are quickly' raised into ridges, as shown in 
Fig. r, which curve inward, and unite to form a cylinder, or tube, as 
shown in Fig. 2. 

In these and the following figures, s is the shell, sm the shell mem- 
l)ranes, w the white, y the yolk of the egg ; bl the blastoderm, whose 
separated layers are not indicated. The figures represent sections 
through the embryo at right angles to the long diameter of the egg. 

24. The tube thus formed is the primitive vertebral column of the 
chick, and is shown at v in the illustrations. Its formation is accom- 
l)anied by depressions, along the outer walls, of the four layers of the 
blastoderm, which by incurvation give rise to the body walls of the 
embrj-o, as seen in Figs. 2 and 3. It will be seen that the body walls 
do not unite upon the under surface, but that the blastoderm, out of 
which the}' are formed, is reflected upward and outward over the surface 
of the 3-olk. As the infolding here described applies not onl}- to the 
sides of the original tube, but to its ends as well, the embryo may at 
this stage be roughl}- described as consisting of two parallel (closed) 
tubes, of which the lower and larger has a slit upon its under surface, 
by means of which communication is kept open with the interior of the 
yolk. 

25. Of the four layers comprising the body walls of the embryo, 
the outer is the epiblast, the inner the hypoblast, and the middle ones, 
the two layers of the mesoblast. The outer two are subsequently to be 
used in the formation of the permanent body walls of the chick, the 
skin, skeleton, and principal muscles ; the inner two will enter into the 
formation of the intestinal tract and other internal organs. 

26. The outer two laj^ers of the blastoderm immediately surround- 
ing the embryo are now drawn up over it on all sides to form a 
closed sac, called the Amnion. It is shown in process of formation 
in Fig. 4, and in its closed form in Fig. 5, where it appears as a 

26 



circle .surrounding the embryo, an opening being left in its lower sur- 
face wliere the slit in the walls of the embryo occurs. In Fig. 6 it 
has lost its circular form in cross section and has been made to con- 
form to the surrounding surfaces of the inner layers of the blasto- 
derm, and the overlying vitelline membrane. 

27. When the outer two layers of the blastoderm are folded up- 
ward around the embryo to form the amnion, as described in par. 26, 
a portion of their outer expanded surfaces is cut oflf, by the junction 
of the amniotic folds over the back of the embr3'o, and their fur- 
ther connection with the embrx^o is completely severed. The severed 
portion is called the chorion, or false amnion, and takes no further 
part in the dev^elopment. 

28. The severance of the chorion from the amnion leaves but two 
living membranes overspreading the general surface of the yolk, the 
hypoblast and the inner la3'er of the mesoblast. The amnion has a 
double wall, of which the inner is the epiblast, the outer the external 
layer of the mesoblast. The two sets of membranes are brought into 
contact within the body of the embryo. 

The cavity of the amnion is filled with a fluid of saline reaction, 
called the amniotic fluid, which is clear and colorless, and by which 
the amniotic sac becomes greatly distended. 

29. The amnion contains no blood vessels. Like its contained 
fluid it is clear and colorless, so that if the shell be broken and 
removed from above it, the embrj-o can be distinctly seen imbedded 
in a pit in the yolk. 

30. The functions of the amnion are the protection of the embryo, 
the secretion of the amniotic fluid, b}^ which its free movement is 
facilitated, and the storage of moisture during the earlj^ stages of 
incubation, to be used at a later period. Its ruptiire by jarring when 
the eggs are turned, or otherwise, is fatal. 

31. The amount of the amniotic fluid varies, not only with the 
stage of incubation, but with the conditions of heat, ventilation and 
moi.sture. In general it is more abundant during the second week 
of incubation, and disappears rapidly during the latter part of the 
third week, when the eggs dry down with corresponding rapidity, 
giving the chick room to get out. 

32. The proper development of the amnion is closely connected 
with the moisture problem, and too little attention has been devoted 
to the subject by poultry Avriters. Having no blood vessels and tak- 
ing no part in the sustenance of the embryo, it has been passed over 
as a practically unimportant organ; as one which the chick could not 

27 





•5 ^.72 




Fig. 1. 



Fig. 2. 



Fig. 3. 






Fig. 4. 



Fig. 5. 



Fig. 6. 



KiGURKS Showing Succr.s.sivE Stages in thk Development ok the Amnion, 



J, shell. 
sm, shell membrane. 
7v, white. 



_v, yolk. 
i/, blastoderm. 
am, amnion. 



ante, amniotic cavity. 
cm, embryo. 
V, vertebral calunm. 



28 



get on without, and yet one with which nature rather than the 
poultryman was concerned. It will, therefore, be worth our while to 
devote some space to its consideration from the standpoint of utility. 

33. The almost universal practice among" operators of incubators, 
and the instruction given by all those manufacturers who advocate 
the use of moisture is to apply it during the latter part of the period 
of incubation. Some manufacturers give instructions to fill the water 
pans on the eleventh day and allow theiu to remain until the hatch 
is over. Others furnish water pans with instruction to add water 
whenever in the judgment of the operator it becomes necessary, that 
is, whenever the air cells seem to be growing too large. However, 
as the air cell seldom grows rapidh^ until after the tenth day, few 
operators, following these instructions, will be likely to add moisture 
before that time. Only two reasons can be given for his mode of pro- 
cedure, either that experience has shown it to be best, or that it is 
nature's method, and therefore to be followed implicitly. 

34. As regards the matter of experience it must be admitted that 
the results obtained by most operators have not been of a character 
to justify them in making any emphatic statements as to what is best. 
Operators generally may have found it more advantageous to add 
moisti:re after the tenth day than to leave it out ; but this does not 
signif}' that it might not have been better to use it earlier, especialh^ 
when we consider that perhaps not one operator in a hundred has 
ever tried using it earlier. The sort of experience which. invariabU* 
follows one course, and that to doubtful advantage, is of little value. 
That this is not an exaggerated vStatement of the case is shown b}- 
the recent reply of an editor to a correspondent who wished to hatch 
200 chicks with incubators, that in order to do so it would be neces- 
sary' to set from 400 to 600 eggs. Evidently there is room for im- 
provement on the general practice. It might be supposed that the 
manufacturers had worked out the problem; but owing to the some- 
what sudden rise of interest in artificial incubation there was little 
time for prolonged experiment, and machines were rushed on the 
market when the principles of incubation were but imperfectly under- 
stood. In addition, it was universally assumed that the purpose of 
moisture was the regulation of the size of the air cell, and it was 
not until about 1S98 that certain manufacturers ventured to disregard 
the air cell as an important factor in artificial incubation. We may 
accordingly assume that the prol)lem has not yet been completel}- solved 
experimentally. 

35. If we turn to nature we find no authority whatever for suppl}'- 
ing moisture in the latter j^art of the incubating period. On the con- 

29 



trary, the indications are that it is supplied in p:reatest abundance 
during the first week of incubation. Some writers have pronounced 
it absurd to suppose that the hen supplies an\- moisture at all to the 
eggs; but a little reflection will show that while she may not use 
water pans, the heat from her body maj' evaporate such moisture as 
may be in her nest, or in the earth beneath it, and that this moisture 
may be brought into direct contact with the eggs. This explains 
why the hen which hides her nest in the woods or in a meadow 
usualh' comes off with a full brood of chicks, while the one that 
sits where we put her, so often comes off with a smaller number. In 
the first case the hen selects a spot where the earth is moist and 
builds her nest near the ground, where the moisture can be utilized; 
in the second, .she is usually vSet in a box, on hay or straw, and under 
cover, vtnder conditions which can furnish but little external moisture. 
Other things being equal, the evaporation will be greatest at the out- 
set of incubation or as soon as the earth beneath has become thor- 
oughly warmed. 

36. In the absence of an}- definite knowledge on the subject, let 
us reason about the matter. It is true the self-st3-led practical poul- 
trynuin has little sympathj- with theories and theorists, preferring more 
definite knowledge, as for instance, wh\- he does not get more eggs, 
what ails his chicks, how to make hens moult early, how to get rid 
of lice, how to build scratching sheds and trap nests ; all important 
matters, but hardly such as to employ all of a thoughtful man's time. 
Theory has its place no less than practice and is often the surest 
and shortest method of arriving at the truth. 

37. A man who had been unfortunate in the matter of fires might 
argue that when a fire gets well under wa}- the only sure means of 
putting it out consists in turning on a full stream of water. In like 
manner it might be argued that under certain conditions a full supply' 
of moisture in the third week of incubation is all that can prevent 
chicks dying in the shell. But as a little water ai)i)lied at the right 
time will often prevent a great conflagration, so a little moisture 
applied to the eggs at the right time ma}- accomplish more than a great 
deal api)lied at the wrong time. It is the beginning of a fire that 
escapes notice ; there is no merit in discovering it after the building 
is half consumed. So the need of moisture in an incubator steals 
u])on us as insidiously as a fire in a garret, and before we are aware 
irreparable danuige may be done. 

3S. If a fertile egg be boiled on the sixth day of incubation for 
ten minutes and then opened, about four fifths of it will be found 
solid, like a fresh one, and would make good eating, while the re- 



mainder can be poured off like water. This liquid portion consists 
chiefly of the amniotic fluid and shows how abundantly it has been 
secreted. A large portion is water, the remainder representing solids 
held in solution. It seems a reasonable assumption that nature has 
some purpose in withdrawing so large an amount of moisture from 
the body of the egg at this period, and that it must in a measure 
defeat her purpose to dissipate it by evaporation. 

An examination of the figures on pages 36 and 43 will show that 
as incubation progresses the 5-olk floats upward until in time it comes 
in direct contact with the shell membranes. In order that this ma}- 
occur it is necessary that the intervening white shoiild be displaced, 
and this is accomi)lished in part by its liquefaction and absorption 
by the amnion, and in part by its settling to the bottom of the egg. 
Liquefaction is brought about through the agenc}^ of the amnion and 
it is extremely important that it should be complete. If through un- 
due evaporation a thin hardened layer of albumen be left between the 
yolk and the shell the consequences are fatal. Either the germ will 
adhere to the shell or the expansion of the blastoderm will be ar- 
rested, though the evil effects in the latter case usualh' do not become 
manifest until a later period. 

39. The upward movement of the 3-olk is hastened by either two 
much ventilation or too high a temperati:re. If the temperature be 
allowed to rise to 110° and to remain at this height for a few hoiirs 
the germs will be found dead and adhering to the shell. It is in 
part to prevent such adherence that the eggs are turned. Surely the 
best temperature for the first week lies between 101° and 102°. 

40. A simple rule may be given by which the operator can decide 
whether the eggs are receiving too much or too little air. On the 
seventh day or earlier, the eyes of the embryo become visible in the 
egg tester. If the amniotic fluid is abundant they will appear as 
large blurred images, and the blood vessels can be made out indis- 
tincth'. This appearance corresponds to a normal development of the 
embrj-o. If the supply of the amniotic fluid is .scant, the eyes will 
appear as small black dots, the blood vessels will be distinct and 
bright, and they are receiving too much air. If on the other hand 
the embryo and blood vessels can with difficulty be made out at all, 
the eggs are receiving too little air. To be on the safe side, it is best 
to keep the temperature low and the ventilation greath' restricted 
during the first week, and more especiall}- during the first four days. 






Fk;. 7. 



Fig. 8. 



Fig. 9. 






Fig. 10. 



Fig II. 



Fig. 12, 



Showing Successive Stages ix the Development of the Umbilical Vesicle. 

Figures 7, 8, 9 represent transverse sectional views. The heavy lines show the extension 
of the umbilical vesicle over the yolk. Fig. 9 shows the position and size of the yolk just 
prior to hatching, and before it is withdrawn into the body of the chick. 

Fig. 10 shows the vascular area of the umbilical vesicle and sinus terminalis, with shell 
removed, at the end of the fourth day ; Fig. 11 the same at the end of the fifth day, the sinus 
terminalis being no longer visible ; Fig. 12 the same, seen from below at the end of the eighth 
day. In the figures y is the yolk, w the white of the egg, am the amnion, um the umbilical 
vesicle, em the embryo, v the vertebral column. 



32 



IX 

The Umbilical Vesicle 

41. That portion of the blastoderm which ramifies over the surface 
of the yolk (see Chapter V), is called the umbilical vesicle. It consists 
originally of four la%'ers, but in the formation of the amnion (see 
par. 27), the outer two are completely cut off from all connection with 
the embryo, leaving onl}^ two layers, the inner being an expansion of 
the hypoblast, the outer the inner layer of the mesoblast. The hypo- 
blast may be considered as the lining membrane of the umbilical 
vesicle, as it is of the intestines, of which it is a continuation. 

42. Within the body of the embrj'o, and out of the substance of the 
inner la3'er of the mesoblast, is formed the heart ; from which one set 
of blood vessels diverge to carry nutriment to the embryo, and another 
to collect it b}^ overspreading the outer layer of the umbilical vesicle. 
We are at present concerned with the latter only. The blood vessels 
emerge from the body of the chick through the opening on the ventral 
surface (par. 24), and branch out over the yolk, beneath and around the 
amnion, as shown in Figs. 7, 8, 9. The heavy lines show the extension 
of the umbilical vesicle, the dotted lines that of the vascular area or 
that portion which is penetrated by blood vessels. In Fig. 10 is shown 
the appearance of a germ and the umbilical vesicle on the fourth day, 
as seen from above with the shell removed. In Fig. 1 1 the vascular 
area is shown greatly extended as it appears on the fifth da}'. While 
in Fig. 12, representing the eighth day of development, the under side 
of the egg is shown, the blood vessels approaching the median line 
from opposite directions. 

The appearance of the egg in the egg tester is not greatly different 
from that shown in Figs. 10, 11, 12, with the shell removed. There is, 
however, one important difference. As shown in Fig. 10, the vascular 
area is bounded by a somewhat circular vein, called the Sinus Terniin- 
alis, by which in part the blood is returned to the heart. In the egg 
from which Fig. 11 was drawn, this vein was not visible to the naked 
eye, and under normal development it can at no time be seen in the egg 
tester. However, if the embryo dies within the first ten days it will 
often appear in the tester as a bright red ring, which is a sure sign of 
death. It is the result of congestion of the blood in the sinus termin- 
alis, and where actual congestion does not take place, it often becomes 

33 



so engorged with blood as to be distinctly seen in the tester, at the same 
time that the remaining blood vessels are remarkabl}- bright and 
prominent, so much so that the inexperienced operator is disposed to 
think the development is excellent. This condition is, however, the 
indication, not of health, but of disease, and is the result of too much 
ventilation. It seldom or never occurs with a full supph- of the amni- 
otic fluid. 

43. The extension of the vascular area over the under surface of 
the yolk is accompanied b}- numerous divisions and subdivisions of the 
main blood vessels until its extreme margin becomes a plexus of capil- 
laries, connecting veins and arteries. The capillary area now expands 
over the surface of the yolk in a reverse direction, until it completely 
encompasses the yolk sac. This is under normal development, but it 
frequently happens that the vascular area fails to encircle the yolk, a 
large portion of the under surface being left bare of blood vessels. In 
this event the area covered by the capillaries, by which nutriment is 
absorbed, is greatly restricted and the subsequent growth of the embr3-o 
is retarded. Tlie cause of this restriction is the inability of the blasto- 
derm to expand freely. That portion of the white immediately sur- 
rounding the yolk is normally more fluid than other portions and facili- 
tates the expansion of the blastoderm, but if it has become hardened 
through evaporation, the blastoderm will form creases or folds along its 
borders and advance but slowh' and so check the expansion of the 
vascular area. When this occurs the folded margins will appear dark 
or black in the tester. The creasing is especially likely to occur along 
the outer borders of the yolk and upon the under svirface. 

44. An examination of the figures from 7 to 12 inclusive will show 
that the yolk gradually loses its spherical form, the amnion upon the 
upper surface floating up against the shell, while the lower surface may 
become flat or concave. When looked at from above, it appears 
elliptical and eventually becomes oval, touching the shell at all points. 
The white is meanwhile either absorbed by the amnion or pressed down- 
ward beneath the yolk, and so collects in the lower half of the egg in a 
condition similar to that of a fresh egg. 

45. Perhaps the most essential thing in artificial incubation is that 
the blastodenn and the vascular area should invest the ^-olk in a speci- 
fied time, and as this should occur earh* in the process of development, 
we can appreciate the importance of a statement made i)y Mr. Hodgson, 
to the effect that there is a missing link in artificial incubation, an un- 
solved problem pertaining to the first days of incubation. Restates 
that eggs transferred to an incubator from hens, hatch much ])etterthan 
when the transference is made from incubators to hens. In order to 

34 



understand why this is, we must bear in mind that our instructions are 
to use moisture during the latter part of the incubating period. The 
trouble lies, not in the incubator, biit in the manner in which it is 
operated. 

The vascular sy.stem of the umbilical vesicle must get around the 
yolk and its capillary system must be full}- developed at an early period 
in order that the nutriment of the yolk maybe absorbed and transferred 
to the body of the embryo. Provision has been made by nature for 
withdrawing what remains of the yolk at hatching time into the abdomen 
of the chick. It is, however, extremely important that the bulk of the 
yolk should be assimilated before instead of after hatching, as one of the 
chief sources of mortality in incubator chicks is in the decomposition of 
the unab.sorbe(l yolk. On the other hand the complete assimilation of 
the \'olk means a larger and stronger chick. Not onlj- is this true, but 
the failure of the vascular area to inclose the yolk will interfere with 
the proper development of the allantois, an organ to be subsequently 
considered. 

46. Ci ranting the importance of the early and complete development 
of the umbilical vesicle, let us see how it is to be ])rought about. The 
essential thing is to get rid of the white overlying the yolk as speedily 
as possible. This is accomplished through the agency of the amnion 
and we ma}- extend or restrict the area of its operations almost at will 
by regulating the supply of moisture. The white of the egg is 
mucilaginous and may be rendered viscid through undue evaporation, 
and if this hardening of the white takes place between the yolk and the 
shell, the expansion of the umbilical vesicle may be retarded or stopped 
altogether. In addition, the white may adhere to the shell, especially 
around the air cell, preventing its normal growth and hindering the 
expansion of the allantois, which must slip in between the shell and 
the yolk. 

47. The sixth day is a critical period for the reason that the va.scular 
area of the umbilical vesicle should at this time be passing to the under 
surface of the yolk and crossing the air cell. If evaporation has been 
profuse, its further extension may be stopped for several days, so that it 
is not uncommon to find the development no further along on the twelfth 
day than it should be on the sixth. The chick may die at this stage, 
or it ma}- live on and be found dead in the shell on the twenty-first 
day. Where the development is arrested about the sixth day, the 
under surface remains persistently clear and yellow for several days. 

48. One of the physiological effects of too much ventilation is a 
serious derangement of the heart, the onh' organ which is functionally- 
active during incubation. The restriction of the vascular area, the 

35 



partial congestion of the blood in the sinus terminalis, and the stimulat- 
ing influence of too much oxygen, at first produce an unnatural activity 
and afterward an enfeebled condition of the heart, due to exhaustion. 
When the chick is hatched it will be listless, sleepy, with a disposition 
to chill and hug the fire, and liable to die suddenly and without 
apparent cause, especially after violent exercise. 

As diarrhoea is usualh* traceable to a chill, such chicks are espe- 
cially liable to suff'er from that di.sease. 



X 

The Allantois 



49. The chief function of the umbilical vesicle is, as we have seen, 
to gather nutriment from the yolk of the egg. The allantois is a 
somewhat similar organ whose function is the absorption of the white. 
The latter appears at a later date than the former and becomes the 
more important organ during the third week of incubation. Each in 
turn acts as the chief respiratory^ organ of the embryo, and for the full 
performance of its functions it is necessary that each should be fully 
developed and at its proper time. 

50. As explained in Chapter IX., the two membranes constituting 
the umbilical vesicle are continuous with those originally lining the 
body walls of the embr3'o. These are subsequently wrought into the 
intestines and internal organs of the chick, and in the process, the neck 
of the umbilical vesicle is greatly contracted. There is thus left a space 
between it and the surrounding abdominal walls. 

The allantois has its origin in a budding process on the rear intes- 
tine, which develops into an elongated tube. B}- its continued growth 
it passes out of the abdomen of the embr\-o between the abdominal walls 
and the neck of the umbilical vesicle, and forthwith expands into a 
flattened bag. It lies exterior to the amnion, and expands over its 
upper surface so as to come into immediate contact with the vitelline and 
shell membranes. It is highh- vascular and secretes a C{uantit3- of fluid 
which facilitates its movements. 

The appearance of the principal blood vessels of the allantois on 
the eighth day is shown in Fig. 15. At this stage the yolk, as seen 
from above is at all points in contact w'ith the shell, except where 
it joins the air cell. Its upper surface is approximately a plane, 
above which lies about two fifths of the contents of the egg, chiefl\- 

36 






Fio. i.^. 



Fig 14. 



Fig. 15. 






Fig. 16. 



Fig. 17. 



Fig 18. 



Figures Showing Successive Stages in the Development of the Allantois 

In Fig. 13 the allantois is seen as a flattened bag originating in the abdomen of the em- 
bryo, and overspreading the upper surface of the yolk and the amnion. In Fig. 14 the allan- 
tois has encircled the greater part of both yolk and white Fig. 15 shows the principal blood 
vessels of the allantois, with shell removed on the eighth day ; Fig. 16 its appearance in the 
egg tester on the tenth day; Fig 17 the same seen from below on the eleventh day. Fig 18 
shows the size of the air cell and the only blood vessel that should be visible on the 19th day. 
X yolk ; re, white ; a/, allantois ; em, embryo ; v, vertebral column. 



37 




/ ^ J 



Fig. 20. 






2 ^ 3 



In,. 21. 



Mr'/D 




/ ^ J 



Fic 22. 



Develoi'MEXT of the Br.-\in and Spi.vai. Cord. 

C, anterior eucephalic vesicle; o, primitive optic vesicle, au, primitive auditor\- vesicle ; 
am, amnion ; vv, vitelline veins, connecting with heart ; /, 2. ?, primitive anterior, middleland 
posterior cerebral vesicles , hmp, hemispheres; olf, olfactory lobe. 



3^ 



in the form of a watery liquid. All of the tinchanged white now lies 
below the 3'olk, which in cross section has the form of a band, as shown 
in Fig. 13. 

The vitelline membrane now envelops everything above the white, 
and the allantois, expanding over its inner surface, eventually encircles 
the yolk, its folds meeting upon its under surface. jNIeanwhile, at the 
point of inflection where the allantois turns upon the under .surface of 
the 3'olk, a fold creeps down the sides of the shell and encircles the 
white. In cross section the allantois therefore eventually takes the 
form of a distorted figure S. It will therefore be seen that the allantois 
in its final form is in contact with the shell membranes at all points, 
and that in addition, a septum pas.ses through the egg, separating the 
white from the yolk. 

51. The blood vessels of the allantois appear in the egg tester 
about the tenth day upon the u])per sxirface, and a day later upon the 
lower. They do not radiate from a point as do those of the umbilical 
vesicle, but traverse it from right to left and irregularly, so that the 
appearance of no two eggs is the same. The}- should be large and 
dark and not too distinct. 

52. When the principal blood vessels of the allantois Iiave come 
into ])lace, the development of its capillaries begins along its terminal 
margins and progresses backward toward its origin. As the effect of 
the capillaries is to darken the interior of the egg when viewed through 
the tester, an egg properly developed will appear nearly or quite opaque 
by the end of the fourteenth daw except for the space occupied In' the 
air cell. 

53. We see now how complete are Nature's arrangements for the 
nourishment of the embryo. One membrane, the umbilical vesicle, 
similar in origin and digestive powers to the intestines, completeU' 
invests the 3'olk ; another, the allantois, embraces within its folds both 
j'olk and white, and each is provided with innumerable capillaries for 
absorbing nutriment and with blood vessels for carrying it into the 
liody of the embr5'o. At the .same time abundant provision is made for 
the aeration of the l)lood. In the earlier stages, when not much air is 
needed, the surface exposed to the action of the air is restricted through 
the agenc}' of the amnion, while a sufficient supply is secured through, 
the umbilical vesicle. While in the later stages, when much more air 
is needed, aeration takes place throughout the whole interior of the 
shell. 

54. The same causes which facilitate the expansion of the umbili- 
cal vesicle, abundance of moisture and a limited supply of air, are 
also favorable to the expansion of the allantois, and it will usuallv 

39 



be found that the proper development of the first insures that of the 
second. The conditions, however, should be but little changed during 
the second week, the ventilation being still restricted, but toward its 
close, when the development of the allantois is complete, the supply of 
air should be increased. If, however, evaporation has been too pro- 
nounced during the first week, it will be necessary to use moisture 
during the last week, but in this case the development will not be 
altogether normal. 

55. The growth of the air cell, which is commonly taken as an 
index to the amount of evaporation that has taken place, is largely 
influenced b}' the supph' of moisture. If the white of the egg over- 
lying the yolk is not completely absorbed, that which remains will 
adhere to the shell and evaporation will not only be retarded, but the air 
cell will be deeph^ concave and appear much smaller than it really is, 
leading the operator to increase the supply of air at a time when it ought 
to be diminished. 

In deciding whether to add moisture, one real!}- should rely upon the 
appearance of the eggs rather than u])on the size of the air cells. Two 
tests should be made, at the end of the fifth and fourteenth da3-s. If the 
embrj'os appear deep seated at the time of the first test, the amnion large, 
the blood vessels not too di.stinct, and the opaque area of the blastoderm 
well advanced over the surface of the yolk, the development is normal. 
To insure its being so it is well enough to give the eggs verj^ little air 
during the first five da3-s, and to leave the incubator doors closed until 
the time for testing arrives. The eggs should be nearly or quite opaque 
by the time the second test is made. However, if the opacit}' covers 
half the egg, including the pointed end, the development may be con- 
sidered satisfactory. If the eggs are not doing well at this time, as 
indicated by an incomplete development of the capillary system, clear 
spaces, blackened areas and bright blood vessels, not much can be done 
toward improving the conditions beyond adding moisture. A few of 
the eggs should be tested about the eighth and eleventh days, to see 
that they are developing properly. We have this simple rule to 
guide us : 

The eggs should be growing dark upon the eighth day and notice- 
ably darker on the eleventh. To render them darker add moisture or 
decrease the supply of air. It is possible to render the eggs pre- 
maturely dark In* following this rule. In this case increase the supply 
of air. 

56. Before the chick leaves the shell, the umbilical vesicle, with 
what remains of the 3'olk, is withdrawn into the abdomen and serves 
as food for a time after hatching. In rare cases the amount of the 

40 



yolk remaining is so j^reat that it can be but partiall\- i)rovided for and 
the chick on hatching? pulls out its bowels and dies. The allantois, 
however, must be left behind, and as the chick must cut through it in 
order to get out it is necessary that at the proper time it should perish, 
the blood which it contains being withdrawn into the bod}- of the chick. 
This normally takes place with the establishment of the pulmonary- 
circulation, but is in part due to the continued growth of the chick. At 
a certain time, assuming that the temperature has been kept at about 
103°, the chick will begin breathing, and ma}- continue to do so for some 
time, owing to the partial aeration of the blood by the allantois. If it 
can break through the shell by pipping, it may live for two or three 
da3-s before getting out. IIowe\er, if the allantois dies prematurel}-, 
the chick can live but a short time on the limited supph' of air within 
the shell. Full grown chicks may therefore die in the shell from either 
of two causes; the allantois may continue to perform its functions until 
the chick becomes enfeebled from inhaling carbon dioxide and dies of 
exhaustion; or the allantois may die prematurely and the chick die 
c[uickly of suffocation. In the first case the hatching may extend over 
two or three or more days, the chicks not hatching imtil long after 
pipping. In the second case the hatching is soon over with, the chicks 
hatching c[uickly after pipping, or else dying. In the first case the 
shells are usually hard and thick and the chicks whicli hatch are subject 
to leg weakness. In the second, the shells are thin and very brittle, and 
the chicks are usually large. In the first case the eggs have had too 
much air during the last half of the incubating period, in the second, 
too little. 

57. Not infrequentl}- the chick dies of strangulation in attempting 
to break through the unabsorbed white of the egg, or it comes out 
covered with slime. This is due to an imperfect development of the 
allantois. What remains of the white is left in the shell, as well as all 
the membranes except the umbilical vesicle. 

58. In running an incubator it is best to meddle with it as little as 
possible. For the first five days it should not be opened under an}- 
circumstances, the attention of the operator being confined to the regu- 
lation of the temperature, which at this stage should not be allowed to 
go above 102°. It ma}- be raised to 103° by the tenth day, but should 
be kept under rather than over that figure until the chicks begin to pip, 
when it may be allowed to run up to 105°. If the temperature at any 
time runs to 106° or over, take out the eggs, turn them and replace 
them at once in the incubator. 



41 



XI 

The Embryo 

59. The develo})ment of the embryo embraces a formative or creative 
period covering the first eleven days of incubation, and a growing 
period, extending over the remaining da3S. A certain amount of 
growth takes phice during the first period, but it is slight in comparison 
with what follows. The egg before incubation contains nothing which 
resembles a chick even in the most remote degree. Onh' the materials 
exist, and the mysterious power which moulds these into a living being. 

60. As described in Chapter V, the first appearance of the embryo 
is in the form of a delicate furrow, called the primitive trace, at the 
original seat of the germ-cell. Lateral ridges arise along its borders 
and curving inward unite to form a canal or tube known as the cerebro- 
spinal axis. This tube is formed from the outer layer of the mesoderm, 
and is lined with epiblastic cells, from which are developed the brain, 
spinal marrow, and the nervous system. 

61. The forward portion of the canal is greatly enlarged to form a 
receptacle for the brain, and as shown in Figs. 19, 20. 21. 22, is divided 
into three parts by lateral constrictions which are known as the anterior, 
middle and posterior cerebral vesicles, and are designated as i, 2, 3, in 
the sectional figures ; o is the primitive optical vesicle, am the amnion, 
au the auricle or ear. vv the vitelline veins, pv the pro-vertebrae. 

62. In Fig. 20 we have a stage of development common to all 
vertebrates, including a spinal cord and three cerebral vesicles. Fig. 21 
represents a higher stage of development. From a protrusion on the 
anterior cephalic vesicle a fourth is developed which eventually becomes 
much larger than the three others combined. Within it, is developed 
the great ma.ss of the brain, its volume being an inde.x to the degree of 
intelligence possessed by any given animal. I'ig. 22 represents a co- 
incident .stage in which the olfactory lobes and nasal passages are 
formed as an outgrowth from the skull. The socket of the eye is 
formed b}' outgrowths from the cranium and the eye from a protrusion 
from the brain itself. The ear is sunk as a pit in the base of the skull, 
and is connected with the primitive posterior cerebral vesicle. 

63. A second and larger tube is formed by the downward incurva- 
tion of the four layers of the bla.stoderm, as described under the 

42 



Amnion. This is the main body cavity, which along- its forward 
portion is greatly contracted to form the neck, while a slit is left upon 
its ventral surface for the free communication with the yolk. From the 
outer layer of the mesoblast, or somato-pleure, the body walls are 
formed and within it are developed the skeleton, the true skin, and the 
voluntary muscles. The inner layer gives rise to the intestines, and 
the various internal organs, of which the hypoblast becomes the lining 
membrane. 

64. A third tube, open at either end, is the primitive heart, which is 
formed from a fold in the inner layer of the mesoblast and lined with 
hypoblastic cells. Numerous other tubes, developed within the same 
membranes, and by the same process of folding, unite to form veins and 
arteries, which become respectively connected with the rear and forward 
ends of the heart. From the hypoblastic cells lining the blood vessels 
are developed blood corpuscles and simultaneously the finst circulation 
of the blood is established. The tubular heart now bends upon itself, 
bringing its two ends together. It is subsequently developed into a 
conical form with inter-communicating chambers. 

65. A fourth tube is the alimentar}^ canal, developed like the heart 
from a fold of the splanchno-pleure and hypoblast. It is at first a blind 
tube, but subsequently communicates with the surface through the 
buccal and anal orifices. B}^ its great elongation and enlargement in 
different portions, the crop, stomach, gizzard, and intestines are 
produced. 

66. A fifth tube springs from the upper portion of the alimentary 
canal, and follows it downward into the body cavity, giving rise to the 
trachea, or windpipe. It divides and subdivides to form the bronchial 
tubes and the finer substance of the lungs. 

67. A sixth tube is developed from the rear intestine, as already 
described, into the allantois, the stalk of which ultimately becomes the 
bladder. From still other tubes are produced the liver, kidneys and 
gall bladder. 

68. The wings and legs spring from the vertebral column, in the 
substance of the somato-pleure, and at first have the form of solid rods 
penetrating the body walls and carrying with them its covering of 
epiblast. The development of the joints begins at the distal extremities 
and proceeds inward. Bones, muscles, nerves, and skin are formed in 
place, and from the ciistis grow feathers, scales and claws. 

69. False limbs give rise to the l^pper and lower mandibles, and the 
remainder of the body framework of the face is developed from processes 
upon the cranium. The eye is an outgrowth from the brain and there- 
fore of epiblastic origin. The ear is sunk in a pit at the base of the 

43 



skull, and its chain of small bones developed from what are supposed 
to be the remains of disused organs of locomotion among its remote 
ancestors. 

70. vSo the structure goes up as if by magic, like a city built by 
genii, with towers and palaces, spires and minarets, in the stillness and 
darkness of night. We know in part the law of sequence and no more. 
Through all the marvelous process we see the operation of an omniscient 
and all-powerful intelligence, working through agencies of whose nature 
we can form ab.solutely no conception. 




44 



Directions for Operating 

" PEEP=0'-DA Y " BROODER 

HV E. I'. HODGSON, PATKNTEE. 



XII 

Set the brooder level, and when out of doors place it in a sheltered 
spot if possible. When starting the lamp for the first time, have only 
a medium flame and allow it to gradually come up to the heat. If a 
good oij is used the lamp will give off no odor and give better satisfac- 
tion. It is well to cut down the black part of the wick every few weeks, 
but at other times simpU* scrape the crust off with a match. 

The chicken-run to the Xo. i, 4 and 5 Brooder is held up by a stick 
under the run. Keep it up for the first day, then drop it and throw a 
little food down it so that the chicks will run down. They will alwaj'S 
come back. Put a small yard, not over the width of the Brooder and 
about three feet long, in front of the Brooder to confine the chicks in 
front until a week old at least, then a long yard can be made. The 
incline to the No. 2 and No. 3 Brooders is held up b\' a stick on the in- 
side of the Sunparlor. It is best to keep it up the first da3^ and nights, 
until the chicks are a week old. 

Regulatixg the Temperature. — By turning the hover it ojjcns 
or closes the register. When opened it allows the hot air to escape 
and reduces the temperature under the hover. The glass slides in all 
brooders except the No. 5 are for ventilation, and in warm weather 
it is well to also ventilate and keep down the temperature b}' raising 
the cover an inch or two. It is an easy matter to run the lamp so 
that there is ver\' little variation in the temperature, between 90 and 
95 degrees for the first few daj'S, then gradually lowering it until 
it is about cSs degrees at the end of the third week. It is then best 
to remove the hover from the brooder, but if the weather is cold, 
the lamp should be kept burning for a week or two longer, then 
remove chickens to some well-constructed coop. All chickens are 
not alike, some requiring more and some less heat, and you should 
be governed accordingh'. For all of our brooders except the No. 3, 

45 



we can supply a small burner, if desired, for warm weather, and it 
will burn much less oil and will not have to be turned so low. 

We will furnish any part of this brooder should it be desired. 

Feeding Chickens. — Hard-boiled eggs chopped fine, shell and all, 
and mixed with about four times its bulk of soaked bread is best. By 
soaking the bread in cold water it makes it crumbl}-, which is more 
desirable than sloppy food. A little bran mixed with it is excellent. 
Feed this twice in the morning, and rolled oats or pinhead oatmeal 
twice in the afternoon. Do not overfeed your chickens, but give them 
what they will eat up clean in a very few minutes. ]More trouble is 
caused by overfeeding young chickens than in any other way. Keep 
them hungrj' until they are about two months old and there will be 
little cau.se for complaint. At the end of three weeks meal and beef 
scraps can be mixed with their soft food, and cracked corn and other fine 
grains may 1)e fed. It is advisable to mix oyster shells with their soft 
food for they will not eat the required amount of grit if it is simply set 
before them in a dish. Keep plent\' of fresh water before them, and 
milk is excellent. 

Care of Brooder. — It should be cleaned out each day and a little 
loam, coal ashes or sand sprinkled on the floor. In warm weather it is 
a mistake to keep the chickens in the brooder too long, and at the end of 
three weeks they should be divided into flocks of 20 to 30 each, and 
placed in coops ; both coops and brooders should be })laced where it is 
shady and on grass land if possible. It is almost impossible to raise 
chickens in a brooder hou.se after warm weather .sets in, and the brooder 
should be put outside. Not over 50 to 60 chickens should be placed in 
anv brooder, as they will not stand crowding. Many brooders no larger 
than this one, are adverti.sed to accommodate from 100 to 150 chickens, 
but it would be only a disappointment to the operator to ])ut so many in 
any brooder. 

Write to the manufacturers for any instructions you need, also, 
report to them your successes and failures in operation. The}- will be 
glad to aid you where they are able to do so. 



Directions 

PEEP O' D.W I'lVE-DOI.L.VR BROODER. 

Set the brooder level, and when out of doors place it in a shel- 
tered spot if possible. When starting the lamp for the first time, 
have only a medium flame and allow it to gradually come up to the 

46 



heat. If a good oil is used, the lamp will give off no odor and give 
better satisfaction. It is well to cut down the black part of the wick 
ever}' few weeks, but at other times simply scrape the crust off with a 
match. If at any time this burner does not give enough heat, it would 
be best to send for our No. 2 burner, which is mailed from the factory at 
fift)' cents each. 

Temperature : 90° to 95° for the first week, then drop to 80° to 85° 
afterward. 

To remove hover, unhook the thermometer and remove it (when 
shipped there is a tack above it to hold it in until j^ou receive the brooder). 
Keep the cotton about the thermometer to prevent the escape of hot air, 
especially the first week. Push the hover forward and lift it out, Also 
see that the hover is pushed back in place, for if not properly- put back 
it will allow the escape of heat from the heater. 

Keep fresh loam, sand, or fineU" sifted coal ashes on the brooder 
floor. A little coarse bran sprinkled on the floor for the first da}- or 
two is good. Never use sawdust. The more often the brooder is 
cleaned the better. 

Don't feed or water ^'our chickens until they are twenty-four hours 
old. 

The glass slides are for ventilation and light. 



Correct Temperature 

It is impossible to give the exact temperature required in a brooder. 
Ninety degrees is generall}' right. Should the chickens show signs of 
crowding about the dome of heater box, it is a sure sign that the tem- 
perature is not high enough, therefore increa.se the temperature until all 
crowding is stopped. It is a good sign to see the chicks lying with 
their heads outside the hover at night, while during the day there is 
seldom need of over 90° of heat. There is little or no danger of over- 
heating your chicks in this brooder, for they will not sta}- under the 
hover if too warm. 

Caution 

The Cap or Top of our burner raises oft' to clean the wick ; and 
when replaced, .see that it is pushed down into place ; and if the 
No. 2 burner is vised (the one that has an inch wick), special care 
should be taken to see that the cap is put on so that the small notch 
at the ba.se fits down over the wick arbor. There is but one way to 

47 



rtH 21 1903 



put on tlie large cap, but the No. i burner (one-half inch wick) can go 
on either way. If these caps are not properl}' set down, the flame will 
not fill out and it will give but little heat and quite a little odor. 

To Rkmovk BiKXKR.^Pry open the wire loop in the connecting 
wire with a screwdriver, and slip it off the arbor loop and unscrew the 
burner. The No. 3 and $5.00 Brooders are fitted with a No. i burner, 
and should more heat be required the No. 2 burner can be used. All 
other brooders are fitted with a No. 2 burner and the No. i can be 
used if the No. 2 is giving more heat than required, at a saving of 
(piite a little oil. 



Caution to Users and Makers of Brooders 

Peep O'Day brooders are fully ])rotected b}- patents Nos. 564,689, 
622,148, and 644,599, belonging to the Cornell Incubator Manufacturing 
Co.; and all persons are hereby w.^rxed against m.\nufacturing or 
OPERATING brooders so made as to infringe upon above mentioned 

ORIGINAL IWTENTS. 

Cornell Incub.vtors are protected by patent No. 683,830, and 
other later i>.\ti-;nts aptliep for. 




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